Highway Safety Manual Training

Safety has become an area of increasing focus in all aspects of transportation planning, design, construction, and operations. Transportation legislation, such as the SAFETEA-LU Act (2005) and the FAST Act (2015), have promoted data driven safety analysis in various programs. The publication of the Highway Safety Manual (2010) and the Supplement (2014) have standardized data driven safety methodology and developed related tools such as spreadsheets and the ISATe (Enhanced Interchange Safety Analysis Toolbox). 

The demand for knowledge and experience in data driven safety analysis has been increasing. This report documents a project to produce data driven safety training for MoDOT trainers. The project developed two training deliverables.

The first is a full-day training for safety staff and engineers. This training covers the fundamentals of data driven safety, rural multilane divided highways, urban/suburban 4-leg signalized intersections, urban 4-lane freeway segments, and four sample applications: design exception, traffic impact study, design build, and safety programming. The second was a 15-minute video that

presents an overview of data-driven safety and is suitable for staff at various levels, even those without formal safety training. A goal of this project is to produce flexible training materials that can meet the training needs of various MoDOT districts and divisions.

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Report number: cmr 20-008
Published: June 2020
Project number: TR201908
Authors: Carlos Sun, Praveen Edara, Yaw Adu-Gyamfi, Mohammadmehdi Zoghifard, and Ziyi Huang

Performing organization: University of Missouri-Columbia

Local Calibration of the Pavement ME for Missouri

The Missouri Department of Transportation (MoDOT) was one of the early adopters of the Mechanistic-Empirical Pavement Design Guide procedure and completed the local calibration using the research grade software in 2009. The emphasis then was on establishing testing and field data collection programs, and calibrating for new designs, as adequate performance data was not available for rehabilitation sections. Since its adoption by the American Association of State Highway and Transportation Officials (AASHTO) and its support for the AASHTOWare Pavement Design ME, several enhancements have been made. MoDOT has made changes to the materials program by increasing use of recycled materials and adding advanced testing capabilities to develop Level 1 materials inputs to the Pavement ME Design procedure. These factors bring to fore the need for recalibration of Pavement ME Design distress and IRI prediction models for Missouri. This study aimed to recalibrate distress models for new and rehabilitated flexible and rigid pavements using Version 2.5.5 of the AASHTOWare Pavement ME program.

This study included calibration sections in Missouri from MoDOT’s pavement management system (PMS) and from the Long-Term Pavement Performance (LTPP) database. Sections covered a range of subgrades, layer material types, thicknesses, climate, traffic, designs, and rehabilitation practices typical for MoDOT. For flexible pavements, New AC, AC over AC, and ACover JPCP designs, and for rigid pavements, New JPCP and Unbonded overlays were considered. Distress models calibrated include Alligator Cracking, Alligator Reflection Cracking, AC Thermal Cracking, Transverse Reflection Cracking, AC Rutting, Total Rutting and Smoothness/International Roughness Index (IRI) for flexible pavements and Transverse Cracking, Transverse Joint Fault, and IRI for rigid pavements. Level 1 laboratory and field data were used for most design inputs. The predictions showed a deviation from global models and therefore we calibrated to reduce error and eliminate bias in all flexible pavement models considered. Sensitivity analyses were used to study the impact of critical parameters. The rigid pavement sections did not exhibit adequate distress development to warrant a recalibration. Until further distress data is collected, the global models are recommended for rigid pavement designs. The study recommends the use of Level 1 field data for future design.

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Report number: cmr 20-007
Published: June 2020
Project number: TR201609
Authors: Leslie Titus-Glover; Chetana Rao, Ph.D.; Suriyanarayanan Sadasivam, Ph.D.
Performing organization: Rao Research and Consulting, LLC

Performance-Based Specifications of FiberReinforced Concrete with Adapted Rheology to Enhance Performance and Reduce SteelReinforcement in Structural Members

The main objective of this research is to propose novel materials for the construction and retrofitting of bridges, including Economical Crack-Free High-Performance Concrete (Eco-Bridge-Crete, or EBC) and Fiber-Reinforced Super-Workable Concrete (FR-SWC). The project seeks to optimize the coupled effect of fiber characteristics, expansive agent (EA), saturated lightweight sand (LWS), and external moist curing on mechanical properties, shrinkage, and corrosion resistance of such classes of high-performance concrete. The project also aims to replace steel reinforcement in flexural members with steel fibers partially. In Task I, Eco-Bridge-Crete mixture design was optimized to reduce drying and restrained expansion and secure high mechanical properties. Eco-Bridge-Crete mixtures were optimized using various shrinkage mitigating strategies, including the use of different contents of CaO-based EA, LWS, and steel fibers as well as different moist curing conditions. The study revealed some synergistic effects among the EA, LWS, and fiber contents and external curing that led to lower shrinkage and restrained expansion and greater strength. The combined use of EA, along with LWS, was shown to reduce concrete conductivity and improve corrosion resistance. Overall, the use of synthetic fibers, EA along with LWS, increased moist curing duration, and concrete cover depth was identified as suitable strategies for improving the corrosion resistance of Eco-Bridge-Crete mixtures. In Task II, the structural performance of reinforced concrete beams cast with FR-SWC mixtures made with different fiber types and reinforcing steel densities was evaluated. The testing involved casting of beam elements with different steel reinforcement densities (0.4 to 0.8 in.2 of steel area in the tension zone). 

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Report number: cmr 20-006
Published: June 2020
Project number: TR201806
Authors: Kamal H. Khayat, PhD, P.Eng.
Performing organization: Missouri University of Science & Technology